Suction-type grinding mill



Aprifl M1, NW H. PETERSON 3,313,494

SUCTION-TYPE GRINDING MILL Filed April '7, 1965 4 Sheets-Sheet 1 F 4- 232 INVENTOR.

Carl fiPeferson ATTORNEYS Q H- PETERSON SUCTION-TYPE GRINDING MILL 4Sheets-Sheet 2 Filed April '7, 1965 INVENTOR.

Carl H. Pefersan ATTORNEYS p W67 c. H. PETERSON 3,313,494

l SUCTION-TYPE GRINDING MILL Filed April 7, 1965 4 Sheecs-Sheet aINVENTOR. Carl H. Pe ferson ATTORNEYS m 9 W57 c. H. PETERSONSUCTION-TYPE GRINDING MILL 4 Sheets-Sheet 4 Filed April '7, 1965INVENTOR. Ca r/ H. Pe Te rson United States Patent 3,313,494SUCTION-TYPE GRINDING MILL Carl H. Peterson, Denver, (3010., assignor toCharles F. Shepherd, Denver, Colo. Filed Apr. 7, 1965, Ser. No. 446,2956 Claims. (Cl. 241-56) This invention relates generally to grindingmills and more particularly to improvements in grinding mills of thesuction type.

Grinding mills of the suction type generally include a grinding chamberinto which coarse materials are introduced for a size reduction and adischarge chamber which draws the ground finer sizes from the grindingchamber. In both chambers there is provided a rotor supporting spacedblades which move at high speeds in proximity to the inner walls of therespective chambers generating centrifugal air movement therein.

In the grinding chamber the impact of the rotor blades with the feedmaterial causes some size reduction but a major portion of the sizereduction results from the attrition of the particles as the centrifugalforce of the rotor blades crowds the material against the inner surfaceof the chamber Walls. This centrifugal action in the grinding chambercauses the coarser sizes to remain on the outer periphery and the finersizes to be displaced toward the center. The fan blades in the dischargechamber draw these finer sizes into the discharge chamber and ejectthese finer sizes through a discharge outlet in the discharge chamber.

Substantial improvement in the grinding action of a suction-typegrinding mill has been attained by improving the action in variousportions of this mill. Accordingly, it is the general object of myinvention to provide a more effective suction-type grinding mill.

It is an object of my invention to provide a simple, durable andefiicient suction-type grinding mill having an improved arrangement forintroducing feed to the grinding chamber.

Another object of my invention is to provide a simple, durable andefficient suction-type grinding mill having a novel blade arrangement onthe rotor in the grinding chamber which produces improved grinding inthe grinding chamber.

It is another object of my invention to provide a simple, durable andefiicient suction-type grinding mill having a novel arrangement of rotorblades and chamber shaping providing improvements in the dischargeaction of the discharge chamber.

A further object of my invention is to provide in a suction-typegrinding mill an improved control of the discharge from the grindingchamber to the discharge chamber of the mill.

Further objects and advantages of this invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize this invention will be pointed out with particularity inthe claims annexed to and forming part of this specification.

In the drawings:

FIG. 1 is a sectional view of a grinding mill embodying my invention;

FIG. 2 is a sectional view of the grinding mill shown in FIG. 1 takenalong line 22;

FIG. 3 is a side elevation view of the drive motor and motor support forthe grinding mill shown in FIG. 1;

FIG. 4 is a partial sectional view of the grinding mill shown in FIG. 1taken along line 44, FIG. 1, showing the flow control between chambers;

FIG. 5 is a partial sectional View of the flow control shown in FIG. 4taken along line 5-5 showing particularly the external control rod;

FIG. 6 is a perspective view of the plate and arm control portion of theflow control assembly shown in separated relationship;

FIG. 7 is a sectional view of the grinding mill shown in FIG. 1 takenalong line 77 showing the interior of the discharge chamber;

FIG. 8 is a rear elevation view of the fan blade; and

FIG. 9 is a side elevation view of the fan blades shown in FIG. 8.

Referring now to the drawings, in FIGS. 1 through 9, the grinding millis illustrated in detail. The grinding mill includes a sectional casingor housing 2 having a base portion 3 for its support in an uprightposition, and including a cylindrical upper portion. Another portionadjoining the cylindrical portion functions as a fan housing 4 attachedto the housing 2 at the rearward end and an end cover 5 is attached tothe housing at the forward or drive end. Housing 2 has its interiorsurface lined with a suitable liner 2a and fan housing 4 has itsinterior surface lined with a suitable liner 4a. Housing 1 generallyencloses what will hereafter be referred to as the grinding chamber 7and fan housing 4 generally encloses what will hereinafter be referredto as a discharge chamber 8. Fan housing 4 has a discharge spout fordischarging ground material from the discharge chamber 8.

A feed inlet or intake spout 19 extends downwartfly and inwardly throughthe upper portion of cover 5 to the upper interior of the grindingchamber 7 to direct a gravitational feed of material into the bottom ofthe grinding chamber. A cover plate 11 is fastened over the outer end offan housing 4 to close the discharge chamber 8 and provide easy accessto the interior thereof.

A horizontally dispose-d shaft 12 extends through the chambers and issupported for rotation at opposite ends of the housing by a bearinghousing 13 and bearing 14 fastened to the cover plate 11 at the rearwardend and a bearing housing 16 and bearing 17 fastened to the end cover 5at the forward end. Shaft 12 terminates at the rearward end in thebearing 14 and extends through the bearing 17 at the forward end at 12afor coupling to a drive motor in a manner described more fullyhereinafter. A hearing 18 is fitted in cover 5 intermediate the ends ofthe housing for additional support of shaft 12 during rotation. A hub 29is afiixed to the shaft 12 Within chamber 7 by a key providing conjointrotation with the shaft.

A disk-like plate 21 having a hollow central portion fits over the hub26 and in a notched portion thereof. The attachment of plate 21 to hub20, its peripheral structure, and components attached thereto are moreclearly shown in FIG. 2. Plate 21 is removably attached to the hub by aplurality of connectors disposed in spaced circumferential relationwhich extend through apertures on the inner surface of the plate. Theouter peripheral sides and end of plate 21 support a plurality of blades22 which are circum ferentially spaced at about angles. Each blade 22has a central slotted portion which extends a substantial distance overthe end and along sides of .plate 21. In section, each blade 22 includesa base surface portion 23 and an adjoining inclined surface portion 24which is inclined forwardly in the direction of rotation of the plate22. Surface portions 23 and 24 provide scoop-like structure to aid inmoving the material in a circular path in chamber 7 in a mannerdescribed more fully hereinafter.

Elongated rod members 25 project from plate 21 and provide a seat foreach surface portion 23. A pair of fasteners, such as bolts, one on eachside of plate 21 extend through member 25 and base portion 23 todetachably fasten each blade 22 to plate 21 for conjoint rotationtherewith.

Plate 21 inwardly of blades 17 has a plurality of apertures 27 which arecircumferentially spaced at about 45 angles. Apertures 27 are disposedon plate 21 so as to provide a substantially alined passage for air andmaterial flow between the inlet it) and outlet of chamber 7. The generalshape of blade 2 corresponds to that of the inner walls of chamber 7 andthere is substantial spacing therebetween for movement of the materialbeing reduced in size. The lower portion of housing 2 above the baseportion 3 is provided with access openings into the lower portion ofchamber 7 which are normally closed by side cover plates 28 on each sideof the housing and which are detachably fastened to housing 2.

The grinding mill is powered by a drive motor 3t) detachably mounted ona base 31 as shown in FIG. 3. Base 31 is connected to the base portion 3through a base extension 32 the width of which will vary to ac commodatedifferent shaft lengths of different motor ratings. Base 3 and motorbase 31 will preferably be secured on the same fiat supporting surface.A flexible coupling 33 is provided between the motor shaft and the shaftextension 12a of the mill shaft. This drive arrangement allow easysubstitution of drive motors for the grinding mill and permits thecustomer to furnish his own motor.

A flow control is provided between chambers 7 and 8 and generallyincludes a stationary regulator plate 35 attached to housing 2 and amovable regulator plate 36. The component structure detail andarrangement of this control is more fully illustrated in FIGS. 4 through6. Plate 35 includes a substantially flat outer portion 37, an inwardlysloping intermediate portion 38 and a fiat inner portion 39 disposed atright angles to the shaft. Inner portion 39 has a central aperture forfitting over hub in close fitting relationship and has a plurality ofspaced radially extending slots 49 which provide a passage betweenchambers 7 and 8.

Movable regulator plate 36 is generally fiat and circular and isdisposed in juxtaposed relation on the upstream side of inner portion39. Plate 36 i similar in shape to inner portion 39 having a centralaperture for fitting over hub 20 in close fitting relationship and aplurality of similarly shaped, spaced, radially-extending slots 42.Plate 36 so disposed is rotatable with respect to portion 39 and willvary the passage through slots 40 from a fully open to a fully closedposition.

Rotation of plate 36 is made through a mechanical control which includesan inner arm 44 directly attached to plate having a gear mesh couplingwith an outer arm 45 directly connected to an exterior control. Arms 44and 45 are disposed on one side of the mill housing and are shaped toextend parallel with the side of regulator plate 35 on the dischargechamber side. The adjoining ends of arms 44 and 45 having meshing teeth46 so that rotational movement of arm 45 will rotate arm 44. An externalconnecting rod 48 extends through an aperture in and is fastened to theouter end of arm 45 for selective rotation on the side of housing 2. Acontrol rod 49 is attached to the extended end of connecting rod 48 forrotating rod 48 in either direction. Thus, rotation of control rod 43 ineither direction from the exterior of housing 2 will rotate movableplate 36 in either direction through arms 44 and 45 and rod 48. Thepassage through the slots 43 in the stationary plate varies from a fullyopen to a fully closed position and by varying the passage through slotsthe grinding size may be regulated. This regulation usually will beperformed at the beginning of the grinding operation and provides a widerange of grinding sizes for the operators selection.

A hub 51 mounted on a sleeve 52 is fitted over shaft 12 in chamber 8 andis fastened to the rearward end of hub 20 for conjoint rotationtherewith. Hub 51 has six equally spaced, radial arms 53. Each said armhas a fan blade 54 attached thereto. An annulus 55 fastens 4 on the sideof each radial arm 53 in a notched portion of each blade for additionalsupport of the blades during high speed rotation.

The shape of the interior of the fan housing 4 which defines dischargechamber 8 and the details of the fan blades are shown in FIGS. 7 through9. Discharge chamber 8 is generally volute in section with shaft 12offset from the center. With this arrangement the fan blades 54 areprogressively distant from the inner wall of the chamber 8 as shown whenrotated from the inner end of the discharge outlet 9 to the outer end ofthe discharge outlet.

Each blade 54 has an outer end portion 57 which is generally rectangularin shape and fits in close proximity to the chamber walls. The inner endportion 58 is tapered on the outer side. A pair of apertures 59 areprovided adjoining the taper for attaching the blade to the hub. Insection, the blade narrows inwardly on both the outer portion and theinner portions on the forward side; the forward side being the forwardface with reference to the direction of rotation which is shown by thedirectional arrow as being in the clockwise direction. On the rearwardside the upper portion has a generally rectangular recess 61 and agenerally triangular recess 62 intermediate the blade ends. Thisparticular shaping of the blade and disposition with respect to thechamber walls increases the centrifugal action in the discharge chamberand imparts a lateral component of force to the air so as to increasethe suction action and more effectively discharge the suspended groundmaterial from the grinding chamber.

In operation of the mill previously described, a coarse material is fedinto intake spout 10 which provides a gravitational feed inlet to theupper portion of the grinding chamber 7 and also supplies the air to thechambers. The feed material falls to the bottom of the grinding chamberuntil entrained in the centrifugal circulation. Grinding blades 22rotating at high speed impinge on and scoop up the circulating solidswhich are entrained in the circulating air flow and are thrown againstthe walls of the chamber. The impact of the blades 22 and the chamberwall causes some size reduction but a major portion of the reductionresults from the attrition action of the particles as the blades crowdthe material against the side of the chamber walls and circulate it inthe centrifugal flow.

In this eentrifu gal action the coarser sizes tend to remain at theouter periphery and the finer sizes are drawn toward the center of thechamber. Circulating air and airborne material pass around the peripheryof the blades 22 and progress laterally through apertures 27. Theseapertures provide a substantially direct flow path for the entering airsupply inducing flow of a substantial amount of air from the inlet tothe outlet of the grinding chamber in which the circulating airbornesolids will be entrained while oversize remains in the grinding chamberuntil reduced to a size which will become airborne.

The fan blades 54 rotating at high speed in the discharge chamber arelonger and develop a higher peripheral speed than the blades in grindingchamber 7 thereby inducing flow which draws the finished productcirculating in the central portion of the grinding chamber 7 through thepassages of slots 40 and 42 and eject this product directly throughdischarge outlet 9. Rotation of the movable plate 36 by control rod 49will change the rate of discharge of the finished product and therebyvary the size of the product discharge from the grinding chamber.

While the apparatus herein described constitutes the preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus and changes may be madewithout departing from the scope of the invention which is defined inthe appended claims.

I claim:

1. In a grinding mill for reducing a material from a coarser size to afiner size, an upright housing having its interior divided into agrinding chamber and a discharge chamber, said housing having an upperfeed inlet for gravitational movement of feed material to the bottom ofthe grinding chamber and an upper outlet in its discharge chamber, ahorizontally disposed shaft extending through the housing and having aportion extending beyond the housing at one end, a rotor mounted on theshaft in the grinding chamber and including a hub portion, a disk-likeconnector member mounted on the hub for conjoint rotation therewith,said connector having a circumferentiallyspaced series of apertures andblade members carried outwardly of said openings with the outer edges ofthe blade members distant from the peripheral wall of the grindingchamber, said blade members being shaped to provide a scoop portion ontheir forward surfaces for imparting centrifugal movement to material inthe grinding chamber, a stationary plate and a movable plate disposed injuxtaposed relation in a passage between the grinding chamber and thedischarge chamber, said plates having a circumferential arrangement ofradially extending slots in general alinement, the movable plate beingrotatable to vary the alinement of its slots with the slots of thestationary plate from a fully open to a fully closed relation forcontrolling the rate of discharge from the grinding chamber, a fanmember mounted on the shaft within the discharge chamber and havingradially-extending blades inclusive of scoop portions for airbornedischarge of finely divided product through the upper outlet, and meansexteriorly of the housing for rotating said shaft.

2. In a grinding mill for reducing material from a coarser size to afiner size, an upright housing having its interior divided into agrinding chamber and a discharge chamber, said housing having an upperfeed inlet for gravitational movement of feed material to the bottom ofthe grinding chamber and an upper outlet in its discharge chamber, ahorizontally disposed shaft extending through the housing and having aportion extending beyond the housing at one end, a rotor mounted on theshaft in the grinding chamber and including a hub portion, a disk-likeconnector member mounted on the hub for conjoint rotation therewith,said connector having a circumferentially-spaced series of apertures andblade members carried outwardly of said openings with the outer edges ofthe blade members distant from the peripheral wall of the grindingchamber, said blade members being shaped to provide a scoop portion ontheir forward surfaces for imparting centrifugal movement to material inthe grinding chamber, a stationary plate and a movable plate disposed injuxtaposed relation in a passage between the grinding chamber and thedischarge chamber, said plates having a circumferential arrangement ofradially extending slots in general alinement, the movable plate beingrotatable to vary the alinement of its slots with the slots of thestationary plate from a fully open to a fully closed relation forcontrolling the rate of discharge from the grinding chamber, a fanmember mounted on the shaft within the discharge chamber and havingradially-extending blades inclusive of scoop portions for airbornedischarge of finely divided product through the upper outlet, meansexteriorly of the housing for rotating said shaft, and means exteriorlyof the housing for rotating said movable plate to vary the size ofproduct passing to the discharge chamber from the grinding chamber.

3. In a grinding mill for reducing a material from a coarser size to afiner size, an upright housing having its interior divided into agrinding chamber and a discharge chamber, said housing having an upperfeed inlet for gravitational movement of feed material to the bottom ofthe grinding chamber and an upper outlet in its discharge chamber, ahorizontally disposed shaft extending through the housing and having aportion extending beyond the housing at one end, a rotor mounted on theshaft in the grinding chamber and including a hub portion, a disk-likeconnector member mounted on the hub for conjoint rotation therewith,said connector having a circumferentially-spaced series of apertures andblade members carried outwardly of said openings with the outer edges ofthe blade members distant from the peripheral wall of the grindingchamber, said blade members being shaped to provide a scoop portion ontheir forward surfaces for imparting centrifugal movement to material inthe grinding chamber, a stationary plate and a movable plate disposed injuxtaposed relation in a passage between the grinding chamber and thedischarge chamber, said plates having a circumferential arrangement ofradially extending slots in general alinement, the connector aperturesand plate slots being in substantial alinement with the feed inlet intothe chamber to provide a substantially horizontal flow path between theinlet and outlet of said grinding chamber, the movable plate beingrotatable to vary the alinement of its slots with the slots of thestationary plate from a fully open to a fully closed relation forcontrolling the rate of discharge from the grinding chamber, a fanmember mounted on the shaft within the discharge chamber and havingradially-extending blades inclusive of scoop portions for airbornedischarge of finely divided product through the upper outlet, and meansexteriorly of the housing for rotating said shaft.

4. In a grinding mill for reducing a material from a coarser size to afiner size, an upright housing having its interior divided into agrinding chamber and a discharge chamber, said housing having an upperfeed inlet for gravitational movement of feed material to the bottom ofthe grinding chamber and an upper outlet in its discharge chamber, ahorizontally disposed shaft extending through the housing and having aportion extending beyond the housing at one end, a rotor mounted on theshaft in the grinding chamber and including a hub portion, a disk-likeconnector member mounted on the hub for conjoint rotation therewith,said connector having a circumferentiallyspaced series of apertures andblade members carried outwardly of said openings with the outer edges ofthe blade members distant from the peripheral wall of the grindingchamber, said blade members being shaped to provide a scoop portion ontheir forward surfaces for imparting centrifugal movement to material inthe grinding chamber, a stationary plate and a movable plate disposed injuxtaposed relation in a passage between the grinding chamber and thedischarge chamber, said stationary plate having a fiat outer portionattached to the housing, an inwardly extending intermediate portion anda flat inner portion, said inner portion and the movable plate having anaperture surrounding the hub portion and a circumferential arrangementof radially extending slots in general alinement, and the movable platebeing rotatable to vary the alinement of its slots with the slots of thestationary plate from a fully open to a fully closed relation forcontrolling the rate of discharge from the grinding chamber, a fanmember mounted on the shaft within the discharge chamber and havingradially-extending blades inclusive of scoop portions in their forwardsurfaces for airborne discharge of finely divided product through theupper outlet, and means exteriorly of the housing for rotating saidshaft.

5. In a grinding mill for reducing a material from a coarser size to afiner size, an upright housing having its interior divided into agrinding chamber and a discharge chamber, said housing having an upperfeed inlet for gravitational movement of feed material to the bottom ofthe grinding chamber and an upper outlet in its discharge chamber, thedischarge chamber being generally volute in sect-ion, a horizontallydisposed shaft extending through the housing in offset relation to saiddischarge chamber and having a portion extending beyond the housing atone end, a rotor mounted on the shaft in the grinding chamber andincluding a hub portion, a disk-like connector member mounted on the hubfor conjoint rotation therewith, said connector having acircumferentiallyspaced series of apertures and blade members carriedoutwardly of said openings with the outer edges of the blade membersdistant from the peripheral wall of the grinding chamber, said blademembers being shaped to provide a scoop portion on their forwardsurfaces for imparting centrifugal movement to material in the grindinggchamber, a stationary plate and a movable plate disposed in juxtaposedrelation in a passage between the grinding chamber and the dischargechamber, said plates having a circumferential arrangement of radiallyextending slots in general alinement, the movable plate being rotatableto vary the alinement of its slots with the slots of the stationaryplate from a fully open to a fully closed relation for controlling therate of discharge from the grinding chamber, a fan member mounted on theshaft within the discharge chamber and having radially-extending bladesinclusive of scoop portions for airborne discharge of finely dividedproduct through the upper outlet, and means exteriorly of the housingfor rotating said shaft.

6. In a grinding mill for reducing a material from a coarser size to afiner size, an upright housing having its interior divided into agrinding chamber and a discharge chamber, said housing having an upperfeed inlet for gravitational movement of feed material to the bottom ofthe grinding chamber and an upper outlet in its discharge chamber, ahorizontally disposed shaft extending through the housing and having aportion extending beyond the housing at one end, a rotor mounted on theshaft in the grinding chamber and including a hub portion, a disk-likeconnector member mounted on the hub for conjoint rotation therewith,said connector having a circumferentially-spaced series of apertures andblade members carried outwardly of said openings with the outer edges ofthe blade members distant from the peripheral wall of the grindingchamber, said blade members being shaped to provide a scoop portion ontheir forward surfaces for imparting centrifugal movement to material inthe grinding chamber, a stationary plate and a movable plate disposed injuxtaposed relation in a passage between the grinding chamber and thedischarge chamber, said plates having a circumferential arrangement ofradially extending slots in general alinement, the movable plate beingrotatable to vary the alinement of its slots with the slots of thestationary plate from a fully open to a fully closed relation forcontrolling the rate of discharge from the grinding chamber, a fanmember mounted on the shaft within the discharge chamber and havingradially-extending blades, each of said blades having an outer endportion of generally rectangular shape in close proximity to the chamberwalls and a tapered inner end portion, the forward surface being taperedon the outer and inner end portions and the rearward surface havingrecess portions for airborne discharge of finely divided product throughthe upper outlet, and means exteriorly of the housing for rotating saidshaft.

References Cited by the Examiner UNITED STATES PATENTS 448,844 3/1891Burnham 24l54 X 795,133 7/1905 Johnson 241-56 1,621,571 3/1927 Witz241-59 X 1,748,050 2/1930 Harrington c 241-56 1,765,309 6/1930 ONeill24156 3,037,712 6/1962 Hoshokawa 24l56 WILLIAM W. DYER, 1a., PrimaryExaminer.

H. F. PEPPER, Assistant Examiner.

1. IN A GRINDING MILL FOR REDUCING A MATERIAL FROM A COARSER SIZE TO AFINER SIZE, AN UPRIGHT HOUSING HAVING ITS INTERIOR DIVIDED INTO AGRINDING CHAMBER AND A DISCHARGE CHAMBER, SAID HOUSING HAVING AN UPPERFEED INLET FOR GRAVITATIONAL MOVEMENT OF FEED MATERIAL TO THE BOTTOM OFTHE GRINDING CHAMBER AND AN UPPER OUTLET IN ITS DISCHARGE CHAMBER, AHORIZONTALLY DISPOSED SHAFT EXTENDING THROUGH THE HOUSING AND HAVING APORTION EXTENDING BEYOND THE HOUSING AT ONE END, A ROTOR MOUNTED ON THESHAFT IN THE GRINDING CHAMBER AND INCLUDING A HUB PORTION, A DISK-LIKECONNECTOR MEMBER MOUNTED ON THE HUB FOR CONJOINT ROTATION THEREWITH,SAID CONNECTOR HAVING A CIRCUMFERENTIALLYSPACED SERIES OF APERTURES ANDBLADE MEMBERS CARRIED OUTWARDLY OF SAID OPENINGS WITH THE OUTER EDGES OFTHE BLADE MEMBERS DISTANT FROM THE PERIPHERAL WALL OF THE GRINDINGCHAMBER, SAID BLADE MEMBERS BEING SHAPED TO PROVIDE A SCOOP PORTION ONTHEIR FORWARD SURFACES FOR IMPARTING CENTRIFUGAL MOVEMENT TO MATERIAL INTHE GRINDING CHAMBER, A STATIONARY PLATE AND A MOVABLE PLATE DISPOSED INJUXTAPOSED RELATION IN A PASSAGE BETWEEN THE GRINDING CHAM-